Chapter 7 Quantum Theory and Atomic Structure - Chapter 7.1...

Chapter7Quantum Theory and Atomic Structure7.1All types of electromagnetic radiation travel as waves at the same speed. They differ in both their frequency and wavelength.7.2a)X-rays < ultraviolet < visible < infrared <microwave < radio waves.b)and c) reverse of the above order7.3a)refraction: the bending of light waves at the boundary of two media, as when light travels from air into water.b)diffraction: the bending of light waves around an object, as when a wave passes through a slit about as wide as its wavelength.c)dispersion: separation of light into its component colors (wavelengths), as when light passes through a prism.d)interference: the bending of light through a series of parallel slits to produce a diffraction pattern of brighter and darker spots.NOTE: Refraction leads to a dispersion effect and diffraction leads to a interference effect.7.4Evidence for the wave model is seen in the phenomena of diffraction and refraction. Evidence for the particle model includes the photoelectric effect and blackbody radiation.7.5He proposed that energy exists only in distinct packages, which he called quanta, and that energy losses and gains by atoms could only be in these units of energy. The magnitude of these gains and losses were whole-number multiples of the frequency: ∆E = nhν.7.6Radiation (light energy) occurs as quanta of electromagnetic radiation, where each packet of energy is called a photon. The energy associated with this photon is fixed by its frequency, E = hν. Since energy depends on frequency, a threshold (minimum) frequency is to be expected. A current will flow as soon as a photon of sufficient energy reaches the metal plate, so there is no time lag.7.7c = λνm10x 12.3=s10x 960m/s10x 3.00=c=m)(2138-νλnm10x 12.3=m1nm10x m10x 12.3=(nm)1192λÅ10x 12.3=m1Å10x m10x 12.3=)Å(12102λ7.8m21.3=s10x 5.93m/s10x 3.00=c=(m)168-νλnm10x 21.3=m1nm10x m21.3=(nm)99λ134

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